Root-zone constraints and plant-based solutions for dryland salinity
Tóm tắt
Limitations to agricultural productivity imposed by the root-zone constraints in Australian dryland soils are severe and need redemption to improve the yields of grain crops and thereby meet world demand. Physical, chemical and biological constraints in soil horizons impose a stress on the plant and restrict plant growth and development. Hardsetting, crusting, compaction, salinity, sodicity, acidity, alkalinity, nutrient deficiencies and toxicities due to boron, carbonates and aluminium are the major factors that cause these constraints. Further, subsoils in agricultural regions in Australia have very low organic matter and biological activity. Dryland salinity is currently given wide attention in the public debate and government policies in Australia, but they only focus on salinity induced by shallow groundwater. However, the occurrence of transient salinity in root-zone layers in the regions where water tables are deep is an important issue with potential for larger economic loss than water table-induced seepage salinity. Root-zone constraints pose a challenge for salinity mitigation in recharge as well as discharge zones. In recharge zones, reduced water movement in sodic horizons results in salt accumulation in the root zone resulting in chemical and physical constraints that reduce transpiration that, in turn, upsets salt balance and plant growth. High salinity in soil and groundwater restricts the ability of plants to reduce water table in discharge zones. Thus plant-based strategies must address different kinds of limitations in soil profiles, both in recharge and discharge zones. In this paper we give an overview of plant response to root-zone constraints but with an emphasis on the processes of salt accumulation in the root-zone of soils. We also examine physical and chemical methods to overcome subsoil limitations, the ability of plants to adapt to and ameliorate these constraints, soil modification by management of agricultural and forestry ecosystems, the use of biological activity, and plant breeding for resistance to the soil constraints. We emphasise that soil scientists in cooperation with agronomists and plant breeders should design site-specific strategies to overcome multiple soil constraints, with vertical and lateral variations, and to develop plant-based solutions for dryland salinity.
Tài liệu tham khảo
Amzallag G N 1999 Plant evolution: Toward an adaptive theory. In Plant Responses to Environmental Stresses. Ed. H R Lerner. pp. 171–245. Marcel Dekker Inc., New York.
Arshad M and Frankenberger W T Jr 1998 Plant growth-regulating substances in the rhizosphere: Microbial production and functions. Adv. Agron. 62, 45–151.
Baker G W 1998 The ecology, management, and benefits of earthworm in agricultural soils, with particular reference to southern Australia. In Earthworm Ecology. Ed. C A Edwards. pp. 229–257. St.Lucia Press, New York.
Bowen G D and Rovira A D 1999 The rhizosphere and its management to improve plant growth. Adv. Agron. 66, 1–102.
Bui E N, Krogh L, Lavado R S, Nachtergaele F O, Toth T and Fitzpatrick R W 1998 Distribution of sodic soils: The world scene. In Sodic Soils: Distribution, Properties, Management and Environmental Consequences. Eds. M E Sumner and R Naidu. pp. 19–33. Oxford University Press, New York.
Clarke C J, George R J, Bell R W and Hatton T J 2002 Dryland salinity in south-western Australia: Its origins, remedies, and future research directions. Aust. J. Soil Res. 40, 93–113.
Cocks P S 2001 Ecology of herbaceous perennial legumes: a review of characteristics that may provide management options for the control of salinity and waterlogging in dryland cropping systems. Aust. J. Agric. Res. 52, 137–151.
Cresswell H P and Kirkegaard J A 1995 Subsoil amelioration by plant roots – the process and the evidence. Aust. J. Soil Res. 33, 221–239.
Eck H V and Unger P W 1985 Soil profile modification for increasing crop production. Adv.Soil Sci. 1, 65–100.
Fisher J A and Scott B J 1993 Are we justified in breeding wheat for tolerance to acid soils in southern New South wales? In Genetic Aspects of Plant and Mineral Nutrition. Eds. P J Randall, E Delhaize, R A Richards and R Munns. pp. 1–8. Kluwer Academic Publications, Dordrecht, The Netherlands.
George R J, Nulsen R A, Ferdowsian R and Raper G P 1999 Interactions between trees and groundwaters in recharge and discharge areas – a survey of Western Australian Sites. Agric.Water Manage. 39, 91–113.
Gupta R K and Abrol I P 1990 Salt-Affected Soils: Their Reclamation and Management for Crop Production. Adv. Soil Sci. 11, 223–288.
Havlin J L, Beaton J D, Tisdale S L and Nelson W L 1999 Soil Fertility and Fertilizers, 6th Ed. pp. 1–499. Prentice Hall, New Jersey.
Helyar K R and Porter W M 1989 Soil acidification, its measurement and the processes involved. In Soil Acidity and Plant Growth. Ed. A D Robson. pp. 61–101. Academic Press, Sydney.
Herczeg A L, Dogramaci S S and Leany F W J 2001 Origin of dissolved salts in a large, semi-arid groundwater system: Murray Basin, Australia. Mar. Freshwat. Res. 52, 41–52.
Itai C 1999 Role of phytohormones in plant responses to stresses. In Plant Responses to Environmental Stresses. Ed. H R Lerner. pp. 287–301. Marcel Dekker Inc., New York.
Jarwal S and Rengasamy P 1998 Gypsum and stubble retention in alkaline sodic soils. Annual Report, Victorian Institute for Dryland Agriculture, Horsham, Australia.
Ma G, Rengasamy P and Rathjen A J 2003 Phytotoxicity of aluminium to wheat plants in high pH solutions. Aust. J. Exp. Agric. 43 (In press).
Marschner H 1995 Mineral Nutrition of Higher Plants, 2nd Ed. Academic Press, London.
Mensforth L J, Thorburn P J, Tyerman S D and Walker G R 1994 Source of water used by riparian Eucalyptus camaldulensis overlying highly saline groundwater. Oecologia 100, 21–28.
Murphy J A, Murphy S L and Samaranayake H 2000 Soil physical constraints and plant growth interactions. In Plant–Environment Interactions. Ed. R E Wilkinson. pp. 387–406. Marcel Dekker, Inc., New York.
Naidu R and Rengasamy P 1993 Ion interactions and constraints to plant nutrition in Australia. Aust. J. Soil Res. 31, 801–819.
National Land & Water Resources Audit 2001 ‘Australian Dryland Salinity Assessment 2000’. NLWRA, Commonwealth of Australia, Canberra.
Nielson N E 1995 Bioavailability, Cycling and Balances of Nutrient in the Soil Plant System. In Integrated Plant Nutrient Systems. Eds. R Dudal and R N Roy. pp. 333–348. Fertiliser and Plant Nutrition Bulletin 12. FAO, Rome.
Oster J D and Jayawardane N S 1998 Agricultural management of sodic soils. In Sodic Soils: Distribution, Properties, Management and Environmental Consequences. Eds. M E Sumner and R Naidu. pp. 125–147. Oxford University Press, New York.
PierreWH, Webb J R and Shrader WD 1971 Quantitative effects of nitrogen fertilizer on the development and downward movement of soil acidity in relation to level of fertilization and crop removal in a continuous corn cropping system. Agron. J. 63, 291–297.
Rathjen A J, Brand J D, Liu C-Y, Paul J G and Cooper D 1999 Breeding for tolerance to soil toxicities. In 11th Australian Plant Breeding Conference Proceedings, Adelaide. pp. 34–39.
Rengasamy P 1997 Sodic soils. In Methods for Assessment of Soil Degradation Eds. R Lal, W H Blum, C Valentine and B A Stewart. pp. 265–277. CRC Press, Boca Raton, Fl.
Rengasamy P 2000 Subsoil constraints and agricultural productivity: 27th Dr. R.V. Tamhane Memorial Lecture. J. Indian Soc. Soil Sci. 48, 674–682.
Rengasamy P 2002 Transient salinity and subsoil constraints to dryland farming in Australian sodic soils: An overview. Aust. J. Exp. Agric. 42, 351–361.
Rengasamy P and Olsson K A 1991 Sodicity and soil structure. Aust. J. Soil Res. 29, 935–952.
Rengasamy P and Sumner M E 1998 Processes involved in sodic behaviour. In Sodic Soils: Distribution, Processes, Management and Environmental Consequences. Eds. M E Sumner and R Naidu. pp. 35–50. Oxford University Press, New York.
Shainberg I and Letey J 1984 Response of Soils to Sodic and saline Conditions. Hilgardia 52, 1–57.
Szabolcs I 1989 Salt-affected Soils. CRC Press: Boca Raton, Fl.
Van Breemen N, Driscoll C T and Mulder J 1983 Acidification and alkalinisation of soils. Plant Soil 75, 283–308.
Voorhees WB 1992 Wheel-induced soil physical limitations to root growth. Adv. Soil Sci. 19, 73–95.
Yunusa I A M, Mele P M, Rab M A, Schefe C R and Beverly C R 2002 Priming of soil structural and hydrological properties by native woody species, annual crops, and a permanent pasture. Aust. J. Soil Res. 40, 207–219.
Zhang L, Dawes WR, Slavich PG, MeyerWS, Thorburn P J, Smith D J and Walker G R 1999 Growth and ground water uptake responses of lucerne to changes in groundwater levels and salinity: Lysimeter, isotope and modelling studies. Agric. Water Manage. 39, 265–282.
Zobel RW1992 Soil environmental constraints to root growth. Adv. Soil Sci. 19, 27–51.